In one conventional remote start system, a driver may toggle a switch on a key fob while positioned away from a vehicle to enable the vehicle to start. In this example, the key fob transmits (i.e., a one-way transmission) a long range radio frequency (RF) command signal (e.g., meters to miles) to a receiver positioned within a controller in the vehicle such that the controller validates the integrity of the RF signal prior to enabling the vehicle to start. The RF command may include various security aspects such as a rolling code protocol. After the RF command signal is validated, the vehicle may start. The driver may also toggle another switch on the key fob to unlock door(s) of the vehicle after the vehicle is started to gain entry into the vehicle.
To ensure that the authorized driver is now in the vehicle after the vehicle is started with the key fob, the driver may be required to insert a key into an ignition switch prior to the vehicle shifting from park to drive. When the key is inserted into the ignition switch and is manually rotated, an RF validation occurs between the controller in the vehicle and a transponder in the key. In this example, the controller may be positioned within 25-50 mm to the ignition switch and the RF validation between transponder on the key and the controller occurs over this short distance. By requiring the RF validation to occur over a short distance coupled with the rotation of the key ensures that the driver is authorized to drive the vehicle and serves as a mechanism to ensure that the driver is “tethered” (or anchored) to the vehicle. The tethering notion further serves to ensure that the driver is indeed authorized to start the vehicle.
In another conventional vehicle start system, a passive entry passive start (PEPS) operation may occur to start the engine of the vehicle. In the PEPS operation, the key fob (or smart fob) may be implemented as a 2-way device. Meaning, the smart fob may receive and transmit frequency based signals. For example, the smart fob and the controller may communicate via low frequency (LF) signals in the event the smart fob and the controller are detected to be in close proximity to one another (e.g., 1 to 3 meters). After the controller has confirmed that the smart fob is an authorized device, the controller may unlock the vehicle to enable the holder of the smart fob to gain entry into the vehicle. Once the driver is in the vehicle, another RF validation may occur between the smart fob and controller to initiate the process and allow the driver to start the vehicle. The driver may then press a brake pedal (assuming the smart fob is validated while in the vehicle) and a push button start switch to start the vehicle. In general, the validation that occurs over the short distance between the smart fob and the controller, coupled with the brake pedal operation, validates that the driver is indeed an authorized driver and is within the vehicle cabin and, more particularly, within the driver's seat. The PEPS operation serves as a mechanism that the driver is “tethered” to the vehicle. The tethering notion serves to ensure that the driver is indeed authorized to start the vehicle.